1. Field of the Invention
This invention is related to an improvement in the structure of a ball grid array substrate and in particular to one having charts for indicating the position of defective chips.
2. Description of the Prior Art
Referring to FIGS. 1 and 2, a label 2 must be used for indicating the position of defective chips on the conventional ball grid array substrate 1 at each of the processing stations. However, it is not only ineconomical to mark the relative positions 21 of the defective chips on the label 2, but also easy for an operator to make mistakes in marking the relative positions of the defective chips, thereby worsening the quality control. In addition, such marking operation must be performed by manual power thus increasing the labor cost.
Therefore, it is an object of the present invention to provide an improved structure of a ball grid array substrate which can obviate and mitigate the above-mentioned drawbacks.